The adoption of multi-hop communication has been proposed for Long Term Evolution (LTE) systems to improve the coverage and capacity of LTE networks. In multi-hop cellular systems, communications between the base station and a user terminal (UT) can take multiple hops with the help of additional intermediate nodes. There are different types of intermediate nodes. Repeaters operate at Layer 1 by amplifying the received signal. Relays decode the received transport block before forwarding and request HARQ retransmissions if necessary, thus operating at Layer 2. Self-backhauling is a Layer 3 relaying technique to improve the coverage and data rates of the LTE network. The terms “relay” and “relaying” are used herein to refer to both layer 2 and layer 3 relaying unless otherwise noted.
When relaying is employed, the packets from multiple user terminals are mapped to a common backhaul radio bearer that carries traffic for many user terminals between the base station (eNB) and relay. To enable users to be multiplexed on the backhaul link between base station and relay, it is necessary that the relay, upon packet arrival, deliver the received packets to the correct user in the downlink direction. When tunneling is employed between the base station and the relay, the user bearer is identified from the GTP-u header of the packet. A drawback of this approach is that the header must be transmitted on the backhaul link creating unnecessary overhead on the radio resource. Further, existing header compression mechanisms, such as Robust Header Compression (RoHC) mechanism cannot be applied to reduce the overhead due to GTP tunneling. The overhead from the GTP-u header and associated UDP/IP headers will lead to unnecessary waste of scarce radio resources.